Latest Evidence From Lead Air Pollution Researcher Shows That Vivergy Air Pollution to Cigarettes Conversion Is An Underestimate

A new review by C. Arden Pope of Brigham Young University, the leading voice on the health impacts of air pollution, calls into question the relevance of his previous work of converting air pollution exposure to cigarette inhalation based on raw exposure statistics.

In one of our previous blogs, we walked through the method we use to convert air pollution exposure to an equivalent number of cigarettes inhaled. This was based on published work of Dr. C. Arden Pope of BYU. But this week, on the MyHealth Beijing blog, Dr. Pope pointed out that under further review, this exposure-based calculation is insufficient for describing the incrementally larger health problems that people who inhale air pollution experience compared to health issues that they would expect to experience when inhaling an equivalent amount of fine particulates from cigarettes.

This all started a few weeks ago when Dr. Richard Muller at the University of California, Berkeley published a study that showed an estimated 4000 Chinese die per day due to outdoor air pollution. Dr. Muller observed that the deaths measured in his study went far beyond the expected number of deaths that these Chinese citizens would experience if they inhaled an equivalent amount of cigarette smoke. In fact, his study showed that based strictly on the health impacts, a Beijing resident inhaled about 40 cigarettes of air pollution every day. This stands in stark contrast to Pope’s estimate, which was around 1/6 of a cigarette a day. A difference by a factor of over 200!

After a discussion, Pope wrote the response posted on MyHealth Beijing which points out the challenges of the strictly exposure-based model versus calculating the exposure based on the resulting health impacts (a chicken or the egg problem). One thing is certain: Pope’s original cigarette calculation is not accurate based on the actual health issues that people experience from outdoor air pollution. The original calculation is an underestimate of the number of cigarettes, but by how much is unclear. Which means the Vivergy air pollution to cigarettes conversion is too low!

A few factors make this calculation complex. First of all, children inhale air pollution 24 hours a day, 365 days a year while their lungs and heart are still developing and have weakened defenses. But you are not going to find any children that smoke cigarettes, so it is challenging to design a controlled experiment since air pollution has a head start by getting into children’s lungs at a more vulnerable point. Also, making the assumption that every unit of air pollution or cigarettes inhaled leads to a directly related increase risk for death may be unfair. It may be more of a logarithmic relationship, where air pollution or cigarettes inhaled at lower levels leads to exponential increases in risk, but as you inhale more of each, the health risks become less per unit of pollution inhaled since your body is already overwhelmed by the pollutants entering the heart and lungs.

That being said, there is one way that we may be able to draw similarities between the two: second-hand smoke. Since there are plenty of children who have inhaled second-hand smoke, scientists can easily study the health effects compared to outdoor air pollution. Pope notes, “In fact, the elevated fine PM [particulate matter] exposures and excess mortality risks for SHS [second-hand smoke] and air pollution are remarkably similar”. Secondhand smoke may be a much more accurate tool for comparison than cigarette smoking itself.

Be on the lookout for an announcement in the coming weeks when we decide how to fairly update our air pollution to cigarettes calculation to reflect this new knowledge. We are very glad to see that an unprecedented level of research is going into this field, and we are happy to be transparent as we try to stay up to date with the latest science.

–The Vivergy Team